I’m an artist, and am planning a new piece. It will be comprised of five panels, each 26” wide x 84” high, with space between them. The entire piece will be approximately 12 feet wide by 7 feet high and suspended from a very high beam. Normally I do my painting on canvas, but this time there will be areas cut out of the surfaces, so I need something solid, like plywood.
(Please tell me whether there’s another material that would work better than plywood. I’m open to all suggestions.)
Both sides of the plywood will be painted with acrylic paint, and all edges, including the cut-out areas, will also be painted. Each panel will have a simple frame made from 7/16 x 2-5/8 molding, attached to the edges of the panels with screws.
I rarely work with plywood, and am concerned about a few issues:
I want to minimize the total weight of the piece.
I want to minimize any warping.
The front surface must be smooth; I don’t care about the back surface.
First of all, are there different grades of plywood, depending on the type of surface or other variables? And would thicker plywood have less tendency to warp than thinner? I’m thinking of a thickness of about 3/8” to 1/2”, but I’m worried that 1/2” will be too heavy. Also, I’m planning on inserting eye hooks into the top edges of the panels (and through the frames) for the purpose of hanging. Can plywood take screws into the edges securely enough that they won’t be pulled out? I’m thinking that this issue would require me to use 1/2” rather than 3/8”, right? And a similar issue with securing the frames with screws: can plywood edges hold screws securely over time? If there is any warping, my fear is that the frames will become separated from the panels.
If it’s thick, good quality ply, then you don’t need to worry about it warping too much and you can probably fix it via screws driven into the sides (providing that you pilot drill them first), but that’ll be heavy.
What orientation will these boards be in when they are in place? I’d be inclined to make some sort of batten frame, then skin it with thin ply or MDF - the only concern there would be sagging of panels in their middles, but only if the whole thing is to be oriented flat/horizontal.
Think about using MDO which is made to take paint well. To minimize warping and weight, screw stiffeners of 1x3 or 1x4 in a cross pattern or an X pattern on the back, then you can get away with 3/8". You can fasten eye hooks (or even aircraft cable directly through drilled holes) more securely to the 1x.
1/4 inch is very warpy. 1/2 inch, not so much, but still you might consider routing a slot into your frame pieces that’ll snugly fit over the edges of the plywood. That’ll give you some dimensional stability.
1/4 inch doesn’t take kindly to screws through the edges. With so few plys, screws tend to rip out.
You can get any quality surface you want at most big box stores. You have to pay for it though.
I had to leave before finishing, but this is generally what I would have said. There are underlayment products such as Tecply that are very thin, yet 5-ply and extremely smooth. Screwing into the end of plywood is probably not going to work for you too well. Perhaps some sort of metal brackets screwed to the plywood, and then hanger wires attached to the brackets would be better?
I’m not fixated on plywood. I think with sheet metal I’d be worried about twisting. And plastic might be too heavy (heavier than comparable plywood, right?)
(Funny you should have asked that while I was typing…)
Take a look at Gatorboard. It’s like foamcore, but instead of paper, it’s skinned with a wood fiber and resin material that takes paint very similarly to MDO, and is much stronger, yet it’s a lot lighter than plywood.
A technical manual for the material suggests that panels can be spliced using wood dowels and white glue, so you can probably figure out a way to suspend the panels after gluing two or three dowels into the top edge. If you use 1/2" thick board, the weight of the material in a 2x7 foot piece will be under five pounds or under six pounds for 3/4" thick. (weights are from shipping info here) The wood frames you’ve proposed will weigh more than the panel. Unless the frames need to be actually wood-grained wood, you could make the frames with Gatorboard, so the entire piece will be very lightweight.
That being the case, I’d construct it like a (cheap) door - make a frame from solid timber, then face it with thin ply - that way, the eyes for hanging it can be eyebolts that go right through the top batten and are secured by washered nuts inside the hollow middle of the thing.
I don’t know if this will work for you but if I were to do something like this, I would make the frame out of 1x4 and attach masonite to it. I would be really surprised to see masonite warp if it’s attached to a frame well enough.
No sheet material should really warp significantly if it’s attached to a stout frame and hung vertically. You could probably even do it with stretched canvas, if you wanted.
I’ve used this for art pieces before and it works very well. On the sizes you mention I highly recommend against a foam core product. They have a strong tendency to warp. By building a frame you could get away with 1/4" ply and have the strength of hanging as Mangetout points out. Buy a good quality A/C grade and sand the surface of any imperfections. Then apply several coats of gesso sanding in between. Good luck.
On preview: Re Mangetout’s last post, Foamcore will. Each surface has it’s own dimensional instability.
You may be right about that - I’ve never really worked with the stuff. I was thinking mainly about single-layer or at least materials of a solid, or single/uniform consistency through their thickness.